All the spectral fits are performed uniformly over our data sample with
the XSPEC package version 12.10.1 [1]}. Spectral
fits to the time-averaged spectra are performed in the energy range 0.3 -10 keV in the case of IMAGING mode exposures and 0.6 - 10 keV in the case of
TIMING mode exposures. Upper and lower confidence intervals are derived for
relevant model parameters at the 68% level. For those fits where
\(\chi ^2_{Norm} > 2.0\) , confidence intervals are not derived and instead
parameter errors are reported at the \(1\sigma \)  level.
